Blood plays a very important role in life-supporting by delivering oxygen to all parts of the body, or by attacking or protecting against nonself that has invaded the body. Blood contains three types of blood components: red blood cells, white blood cells and platelets. The white blood cells have a major and important function to protect a living body against nonself that has invaded the body, and they are classified into neutrophils, eosinophils, basophils, monocytes and lymphocytes. Accordingly, reduction in number of white blood cells disenables a living body to attack or eliminate pathogens that have entered the body, resulting in easy infection.
Leukemia is a disease in which white blood cells are malignantly transformed and proliferate mainly in bone marrow. Leukemia is subdivided into chronic leukemia and acute leukemia depending on the length of time in which it progresses when untreated, and each form is further divided into mygloid leukemia and lymphoblastic leukemia. Advanced leukemia destroys hematopoietic system and causes abnormalities such as reduction of normal white blood cells or platelets and anemia. And symptoms such as easy infection and bleeding tendency become clinically evident. When such hematopoietic dysfunction becomes worse, maintaining life will be threatened. Thus, leukemia is a fatal disease if untreated. Malignant lymphoma is a disease in which neoplastic lymphocytes proliferate mainly in lymph nodes, and is divided into Hodgkin lymphoma and non-Hodgkin lymphoma. Prognoses are varied depending on the lymphoma form, and a non-negligible number of cases result in death.
Hematopoietic tumors such as leukemia and malignant lymphoma have been addressed by killing tumor cells or normalizing the bone marrow function. Hematopoietic stem cell transplantation is one of such treatments. Each hematopoietic stem cell possesses capability to produce mature blood cells such as red blood cells and white blood cells, in other words, hematopoietic stem cells are multilineage potential, and they also have the potential to self-renew. Thus, they are mother cells for all the hematopoietic cells. Normal hematopoietic function may be recovered by eradicating tumor cells such as leukemia cells and malignant lymphoma cells by intense regimen of chemotherapy and radiation therapy and thereafter by transplanting hematopoietic stem cells.
Graft-versus-host disease that occurs after blood transfusion or stem cell transplantation is a serious side effect that should be addressed. Of the hematopoietic stem cell transplantations, allogeneic hematopoietic stem cell transplantation is often complicated with acute graft-versus-host disease (referred to as GVHD hereinafter) as an early complication. Acute GVHD has a mechanism wherein activated T cells present in a graft from a donor recognize human leukocyte antigens (HLA) that express on the surface of white blood cells of a recipient (patient) as foreign and thereby the cytotoxic donor T cells attack cells of the recipient as foreign (Non-Patent Document 1). Patients having acute GVHD develop fever, skin rashes on limbs, face and trunk, liver damages with increased bilirubin, and digestive symptoms such as stomachache and diarrhea. GVHD is generally diagnosed by pathological examination on biopsy specimens of skin, liver and large intestine, but pathological findings are frequently not typical. Further, obtaining pathological materials is often difficult. Thus, there are many cases where this disease is diagnosed by clinical manifestations (Non-Patent Document 2).
A general choice for early treatment of acute GVHD is administration of steroids. Steroids are effective for acute GVHD but may cause serious side effects such as infection with bacteria and viruses, and therefore use thereof must be considered carefully. On the other hand, delay in starting the treatment of acute GVHD can invite a life-threatening result. Due to this dilemma, how to diagnose acute GVHD in clinical cases is a critical problem that influences the success of transplantation. At present, there are no methods capable of predicting the onset of graft-versus-host disease after bone marrow transplantation.
It is demanded that data should be provided which are useful as direct evidence in the diagnosis of acute GVHD. Clinical experts expect that an index is represented to allow for primary linking of a target identified acute GVHD with physiological and biochemical changes associated with immune responses, based on statistical significance. Further, there is a demand for data contributing to the prediction of probability of disease development and the estimation of risk of the development. However, no test methods for providing such data have been established for this disease. Thus, development of such test methods has been desired.
Needless to say, it is important that methods to effectively prevent or treat GVHD as well as the aforementioned test methods should be established and pharmaceutical preparations used for these methods should be developed.    Non-Patent Document 1: Ferranra J L, Redddy P., Pathophysiology of graft-versus-host disease, Seminar in Hematology, 43: 3-10, 2006    Non-Patent Document 2: Atsushi KATO, “Complications of hematopoietic stem cell transplantation and the treatment”, 1. Graft-versus-host disease (GVHD)”, Magazine from The Japanese Society of Internal Medicine, 94:67-1343, 2005